Thin films of compounds and alloy compounds of Group III and Group V elements

Abstract

A thin film of a compound or alloy compound of Group III and Group V elements, particularly of gallium arsenide or gallium arsenide compounds, is produced by impinging, e.g. spraying, onto a heated substrate a liquid or liquids comprising molecules carrying the constituent elements of the desired film. The constituent elements react together on or immediately above the heated substrate to form the desired compound or alloy compound which is deposited on the substrate in the form of a thin film. The resulting thin films may be used in solar cells and other opto-electronic devices.

I claim: 
     
       1. A method of producing a thin film of gallium arsenide comprising impinging onto a heated substrate a solution of gallium arsenate or a precursor thereof with an inert gas propellant, in a reducing gaseous atmosphere. 
     
     
       2. A method according to claim 1, wherein the substrate is selected from amongst glass, conductive oxide coated glass, graphite and metal coated graphite. 
     
     
       3. A method according to claim 1, wherein the substrate temperature is in the range 200° C. and 750° C. 
     
     
       4. A method of producing a thin film of gallium arsenide comprising impinging onto a heated substrate a solution of a gallium/arsenic complex with an inert gas propelled in an inert or reducing atmosphere, wherein the gallium/arsenic complex is formed from precursors of the type R 3  Ga where R is phenyl chloride, and AsT 3  where T is chlorine, methyl, ethyl or phenyl. 
     
     
       5. A method of producing a thin film of gallium arsenide comprising impinging onto a heated substrate a polymeric complex formed between trimethyl gallium and methyl/phenyl arsine, using an inert propellant gas in an inert atmosphere. 
     
     
       6. A method according to claim 5, wherein the substrate is selected from amongst glass, conductive oxide coated glass, graphite and metal coated graphite. 
     
     
       7. A method according to claim 5, wherein the substrate temperature is in the range 200° C. and 750° C.